The application of urea and cow manure on ultisol soil for mustard greens (Brassica Juncea L) aims to determine the treatment of cattle fertilizer on increasing leaf area, root volume and plant fresh weight. as well as the interaction of giving oxen fertilizer (t/ha) and urea fertilizer to mustard greens. This research was conducted in N4 Village with a height of 18 meters above sea level in Labuhanbatu Regency from December 2020 to March 2021. The study will be conducted with a factorial group design. The first factor is the provision of factorial Randomized Block Design (RAK) which consists of 2 factors, the first factor is Ox manure (K) which consists of 3 levels and the second factor is the provision of Urea fertilizer which consists of 2 dose levels, so that 6 treatment combinations are obtained. - 4 replicates each, resulting in 24 plots. Each plot consisted of 25 plants and 5 plants were taken as samples. Parameters observed were plant height (cm), number of leaves (strands), leaf area (cm2), root volume (ml) and plant fresh weight (g). The data obtained from the results of the study were statistically analyzed by means of variance and continued with the Duncan's New Multiple Range Test (DNMRT) at a level of 5%. The results of the study. urea dose of 100 kg/ha was able to produce an increase in leaf area, root volume and plant fresh weight. As well as the interaction of the application of ox-fertilizer (t/ha) and urea fertilizer gave a significant effect on the parameters of leaf area, root volume and plant fresh weight.

Badan Penelitian dan Pengembangan Pertanian Kementerian Pertanian. 2012. Petunjuk Teknis Analisis Kimia Tanah, Tanaman, Air dan Pupuk. Edisi 2. Bogor. 204 hal

Cahyono, B. 2003. Teknik dan Strategi Budidaya Sawi Hijau. Yayasan Pustaka Nusantara. Yogyakarta.

Gardner, F.P., dkk. 1991. Fisiologi Tanaman Budidaya. (Edisi Terjemahan oleh Herawati Susilo dan Subiyanto) Jakarta: Universitas Indonesia Press 428.

Gomez, K.A. and Gomez, A.A., 1995. Prosedur statistik untuk penelitian pertanian Edisi Kedua. Sjamsuddin E, Baharsjah JS, penerjemah. Jakarta (ID): UI pr. Terjemahan dari: Statistical Procedures for Agricultural Research.

Harahap, F. S., & Sari, P. M. (2019). Growth and production response of plant pakcoy (brassica rapa l) on use of nasa light organic fertilizer. Jurnal Pertanian Tropik, 6(2), 222-226.

Harahap, F. S., & Walida, H. (2019). Pemberian abu sekam padi dan jerami padi untuk pertumbuhan serta serapan tanaman jagung manis (Zea mays L.) pada tanah Ultisol di Kecamatan Rantau Selatan. Jurnal Agroplasma, 6(2), 12-18..

Harahap, F. S., Oesman, R., Fadhillah, W., & Nasution, A. P. (2021). Penentuan Bulk Density Ultisol Di Lahan Praktek Terbuka Universitas Labuhanbatu. AGROVITAL: Jurnal Ilmu Pertanian, 6(2), 56-59.

Harahap, F. S., Rahmaniah, R., Sidabuke, S. H., & Zuhirsyan, M. (2021). Evaluasi kesesuaian lahan tanaman sorgum (shorgum bicolor) di kecamatan bilah barat, kabupaten labuhanbatu. Jurnal Tanah dan Sumberdaya Lahan, 8(1), 231-238.

Harahap, F. S., Roswita, O., & Iman, A. (2020). Supply liquid organic fertilizer NASA and rice husk ash to the chemical properties of the soil on the tomato plant. International Journal of Science, Technology & Management, 1(3), 185-189.

Harahap, F. S., Walida, H., Dalimunthe, B. A., Rauf, A., Sidabuke, S. H., & Hasibuan, R. (2020). The use of municipal solid waste composition in degradated waste soil effectiveness in aras kabu village, beringin subdistrict, deli serdang district. Agrinula, 3(1), 19-27.

Hartatik, W., D. Setyorini, L. R. Widowati dan S. Widati. 2005. Laporan Akhir Penelitin Teknologi Pengelolaan Hara Pada Budidaya Pertanian Organik. Laporan Bagian Proyek Penelitian Sumberdaya Tanah dan Proyek Pengkajian Teknologi Pertanian Persentatif.

Haryanto, B., Suhartini, T., Rahayu, E., dan Sunarjo. 2006. Sawi dan selada. Penebar Swadaya, Jakarta.

Hayati, E., Sabarudin., dan Rahmawati. 2012. Pengaruh jumlah mata tunas dan komposisi media tanam terhadap pertumbuhan setek tanaman jarak pagar (Jatropha curcas L.). Agrivista. 3:129-134.

Heddy, S. 1987. Hormon Tumbuhan. PT. Rajawali . Jakarta

Irwan. 2005. Pengaruh Dosis Karci dan Pupuk kadang Lembu (t/ha) Terhadap Pertumbuhan dan Hasil Tanaman Sawi (Brassica juncea L.) Yang Dibudidayakan secara Organik.

Kelik, W. 2010. Pengaruh konsentrasi dan frekuensi pemberian pupuk organik cair hasil perombakan anaerob limbah makanan terhadap pertumbuhan sawi (Brasica juncea L.) [Skripsi Univ.11 Maret] Surakarta.

Moenandir J. 2004. Prinsip - Prinsip Utama Cara Menyukseskan Produksi Pertanian. Fakultas Pertanian, Universitas Brawijaya. Malang.

Nyakpa, M. Y, A, M. Lubis. M, A. Pulung, Amrah, A. Munawar, G, B. Hong, N. Hakim. 1988. Kesuburan Tanah. Universitas Lampung Press.

Peraturan Menteri Pertanian No. 70/Permentan/SR.140/10/201 1. Pupuk Organik, Pupuk Hayati, dan Pembenah Tanah - PP No.18 Tahun 1999 tentang Pengelolaan Limbah B3.

Plaster E. J. 2003. Soil Science and Mangement. Delmar Learning Inc. 4th ed United States. 384 p.

Pranata, A.S. 2010. Meningkatkan Hasil Panen dengan Pupuk Organik. Agromedia Pustaka, Jakarta.

Sarief, S. 1993. Kesuburan dan Pemupukan Tanah Pertanian. Pustaka Buana. Jakarta

Syukur, A., 2006. Kajian pengaruh pemberian macam pupuk organik terhadap pertumbuhan dan hasil tanaman jahe di Inceptisol, Karanganyar. Jurnal Ilmu Tanah dan Lingkungan, 6(2006).

Tan, K. H. 1993. Environmental soil science. Marcel Dekker. Inc, New York.

Walida, H., Harahap, F. S., Dalimunthe, B. A., Hasibuan, R., Nasution, A. P., & Sidabuke, S. H. (2020). Pengaruh Pemberian Pupuk Urea Dan Pupuk Kandang Kambing Terhadap Beberapa Sifat Kimia Tanah Dan Hasil Tanaman Sawi Hijau. Jurnal Tanah dan Sumberdaya Lahan, 7(2), 283-289.

Wijaya, K., 2010. Pengaruh konsentrasi dan frekuensi pemberian pupuk organik cair hasil perombakan anaerob limbah makanan terhadap pertumbuhan tanaman sawi (Brassica juncea l.).